Huge paws with very no­tice­able claws, ef­fort­lessly tear thick shards of bark from the trunk. I can’t help but con­sider whether my torso would put up any more re­sis­tance if he charged at us. In re­al­ity though, the bear is more likely to flee in fear and to climb a tree, than at­tack, Pete re­as­sur­ingly ex­plains.

Rangers es­ti­mate 300-500 brown bears can be found in Amer­ica’s old­est gov­ern­ment-owned park – it cel­e­brates its 125th an­niver­sary this year.

They’ll of­ten en­croach on camp grounds in search of food and reg­u­larly wind up in hu­mane bear traps dot­ted around the park, giv­ing rangers the chance to mea­sure and ex­am­ine them, be­fore re­leas­ing them in less busy ar­eas.

But as I peer through a bush, desperately try­ing to fo­cus my cam­era for that one bril­liant shot, I feel re­mark­ably alone, shar­ing the fleet­ing ex­pe­ri­ence with noth­ing but Na­ture it­self.

That is, I came to re­alise, one of the real as­sets of Yosemite. For a park that sees an es­ti­mated 3.7 mil­lion vis­i­tors a year, most of whom spend all their time in Yosemite Val­ley (which oc­cu­pies only one per cent of the park), it’s re­mark­ably easy to find tran­quil­lity.

We con­tinue our walk, from the vis­i­tors’ cen­tre in the val­ley to Mir­ror Lake, at the base of Half Dome, a gran­ite peak ris­ing to 4,800 feet. It’s a popular as­cent for am­a­teur rock climbers, who can trek up the back face, us­ing the ropes and chains per­ma­nently in place.

I can only imag­ine the view from the top is as spec­tac­u­lar as it is from the bot­tom, when I see the moun­tain’s re­flec­tion in the still wa­ter.

Awestruck at the beauty be­fore us, we sit in si­lence un­til our guide en­cour­ages us to read a se­lec­tion of quotes from Scot­tish- born nat­u­ral­ist John Muir, who was writ­ing about the park 140 years be­fore I ar­rived.

“I only went out for a walk, and fi­nally con­cluded to stay out till sun­down. For go­ing out, I found, was re­ally go­ing in,” Muir wrote, in the years Yosemite was his muse.

It’s true, the park does draw you in and it had taken our small group about an hour to walk only two miles, tak­ing in scenery, mar­vel­ling at the sky-scrap­ing cedars and se­quoias, and spot­ting the na­tive fauna.

The open air train tour is also a popular op­tion for day trip­pers, who wish to see the main sights in a short pe­riod. I’ve never re­ally taken to sight­see­ing buses, but our ‘train’ is more than that. Sarah, our guide, is as pas­sion­ate as any other ranger in the park, and a wealth of in­for­ma­tion cas­cades over us as we pass across the val­ley floor.

After a few short photo stops, we ar­rive at the ul­ti­mate view in Yosemite, op­po­site Wa­wona Tun­nel, the first vista for most vis­i­tors.

We can see across the en­tire val­ley, spot­ting the moun­tains El Cap­i­tan and Half Dome, Dana Mead­ows and sev­eral sea­sonal wa­ter­falls, all of which are highly pho­to­genic.

The ad­vance of tech­nol­ogy to record the mo­ment amuses me, when I con­sider how 150 years ago, when Abra­ham Lin­coln signed the Yosemite Grant Act, des­ig­nat­ing the re­gion to be pre­served for its nat­u­ral beauty and for pub­lic use, the only thing vis­i­tors would take away then were their mem­o­ries.

That leg­is­la­tion paved the way for Yel­low­stone to be­come the coun­try’s first fed­eral park a few years later, and the es­tab­lish­ment of Amer­ica’s Na­tional Park pro­gram as it’s known to­day. Yosemite joined the rest after Pres­i­dent Roo­sevelt spent a few nights in it at Muir’s invitation, and fell in love with it.

With vis­i­tors in the mil­lions now, great ef­forts are be­ing made to pre­serve the re­gion, with almost 90 per cent of the park now des­ig­nated as wilder­ness. Ar­ti­fi­cial in­duce­ments to visit the park have also been cur­tailed, such as the nightly ‘fire­fall’, where glow­ing em­bers were pushed off a cliff face to cre­ate an ad­mit­tedly spec­tac­u­lar wa­ter­fall of fire.

It would be easy to spend weeks ex­plor­ing this mag­i­cal cor­ner of Cal­i­for­nia and get lost in its grandeur, as Muir once did. How­ever, it would be un­think­able to visit Amer­ica’s sunny west coast with­out sam­pling some of its world-class wines.

So my Trafal­gar tour winds its way to Sonoma County, next to the well-known Napa Val­ley, where the wine is equally as ex­quis­ite, for a les­son in blend­ing a fine red. I’ll hap­pily ad­mit, I’m no con­nois­seur, but I’m in­trigued by the sci­en­tific ap­proach we’re taught, to de­velop our own for­mula at Ravenswood Win­ery’s ware­house; eight units of Pe­tite Sirah, four units of Caber­net and eight units of Zin­fan­del seems a pretty good mix to me.

After a leisurely start the fol­low­ing morn­ing, we drive to the town of Sonoma to pre­pare lunch at Ramekins Culi­nary School. I had marked this event as one of the high­lights of our es­corted tour and soon find my­self heav­ily in­vested in a New York- style cheese­cake.

A pair of pa­tient chefs guide us through prepa­ra­tions for each course, for what ends up be­ing a de­li­cious meal ahead of our short drive to San Francisco.

I find my­self bound­ing around our coach with youth­ful en­thu­si­asm as we ap­proach the Golden Gate bridge from the north, which is as im­pres­sive as I had al­ways imag­ined.

We step out of our coach to stroll across, tak­ing in the spec­tac­u­lar views across San Francisco Bay, the city’s sky­line and the in­fa­mous Al­ca­traz Is­land.

Back in the coach, we head to Chi­na­town, the hip Mis­sion and Castro dis­tricts, and Haight-Ash­bury, the cen­tre of the Sum­mer of Love move­ment in the late 1960s. Thou­sands of young Americans crashed in age­ing Vic­to­rian houses in that sub­urb, to share peace, love and a few il­licit sub­stances, in what is now re­garded as a grand so­cial ex­per­i­ment.

And although the area has changed sig­nif­i­cantly in the last 45 years, the friendly spirit re­mains across San Francisco. In a one-block stretch, I’m stopped for a hug, asked where I’m from and given the chance to take a photo of some lo­cals pos­ing in front of one of the city’s well crafted mu­rals.

But my thoughts drift back to Yosemite, where it’s easy to imag­ine that noth­ing has changed in cen­turies and, like Muir, I hope it never will.

To para­phrase the Scots­man: “The moun­tains are call­ing and you must go.”